🚀 go-pugleaf

Archive-name: auto/sci.astro.hubble/Tiny-Tim-v2-1-HST-PSF-maker-now-available

  Version 2.1 of the Tiny Tim HST PSF generator has been placed on STEIS
  (anonymous ftp to stsci.edu, look in the software/tinytim directory). 

  Tiny Tim can generate PSFs for the HST WFPC, FOC f48, FOC f96, WFPC II,
  and COSTAR corrected FOC cameras.  It is written in C and is portable
  to most 32 bit systems. 
 
  Version 2.1 includes the following :

  - The pixel integration method has been changed so that the number of
    samples used in the sinc interpolation increases until a convergence
    criterion is reached.  This gets rid of nearly all abnormal pixel 
    values which were far too common in V2.0, especially in the corrected
    cameras.

  - The file i/o routines were modified to use RMS conventions under VMS.
    This significantly increases their speed.  This was where Tiny Tim was
    choking when UV FOC PSFs were being computed (I hate all of those VMS
    file formats!).

  - A bug in the FITS writer which caused pixel value errors on the VMS side 
    was fixed.

  - The FOC pixel size was set to 25 microns, which provides a plate scale in 
    closer agreement to that resulting from the pipeline geometric correction.

  - The mirror move of 23 August 1992 was added to the aberration table, along 
    with an updated desorption equation.  The WFPC aberrations now include
    coma.

  - The numbering of the WFPC II cameras was changed, and the 45 degree
    rotation of PC II spiders with respect to the OTA spiders was taken out
    since JPL has changed things.

  - Parameter files from v2.0 are NOT compatible with v2.1.

 Other notes :

  - The flux values returned are in electrons per second of a V=10 star.
    To convert to WFPC ADUs, for instance, divide by 7.5.

  - The speed on Tiny Tim on VAX systems can be highly dependent on your
    working set extent quota (this is the maximum amount of RAM memory
    a process can use).  Do a 'show working' at the DCL prompt to see
    how large your extent is (the value given is in pages, 512 bytes per page).
    If you have enough memory on your computer, consider having this quota
    increased (be sure that the system's extent is also enough).  See your
    system manager about this.

 Tiny Tim is NOT an official product of STScI, which is not responsible for
 its support.  I will support it as time and conditions allow.

 John Krist
 krist@stsci.edu
 Space Telescope Science Institute
 Baltimore, MD